Tri-Flow oil is your and your machines bestest friend.
For parts, belts, wiring, my favorite place is Sew-Classic {
http://www.shop.sew-classic.com/ }. There are some other places too, but Sew-Classic has pretty good prices and ships quickly.
Go easy on the finish, cotton balls and oil and for the rusted parts remove them and give them an Evapo-Rust bath. After that some Never Dull or other good polish will bring out what shine they have left.
As for the cabinet, if I can bring a water soaked treadle back to life I'm sure your cabinet can be refurbished.
Joe